Refine the README

Author: pelson

MANIFEST.in

@@ -4,7 +4,30 @@ A web interface to browse and search packages in **any** simple package reposito
 
 Built using FastAPI and the [simple-repository](https://github.com/simple-repository/simple-repository) core library.
 
-## Example
+## Usage
+
+Install from PyPI:
+
+```bash
+python -m pip install simple-repository-browser
+```
+
+And run:
+
+```bash
+simple-repository-browser
+```
+
+(or alternatively ``python -m simple_repository_browser``)
+
+By default, this will use the repository at PyPI (https://pypi.org/simple/). You can point it to a custom
+repository by passing the URL to the project list endpoint (the base URL according to PEP-503):
+
+```bash
+simple-repository-browser https://my-custom-repository.example.com/foo/simple/
+```
+
+## Screenshots:
 
 Homepage:
 
@@ -19,3 +42,36 @@ Search:
 Project page:
 
 ![example project page](https://raw.githubusercontent.com/simple-repository/simple-repository-browser/main/screenshots/project.png)
+
+
+
+## Runtime details
+
+```simple-repository-browser``` exposes a FastAPI application, and it runs the application in a single ``uvicorn`` worker.
+Metadata that is computed will be cached in the ``$XDG_CACHE_DIR/simple-repository-browser`` directory. This cache is not
+intended to be shared among different repository URLs, and is unlikely to work for multiple ``simple-repository-browser``
+versions. There is currently no intelligent cache invalidation for those cases.
+
+
+## Development
+
+In order to build the ``simple-repository-browser``, first:
+
+```bash
+cd javascript
+npm install --include=dev
+npm run build
+cd ..
+```
+
+And then the normal installation procedure applies:
+
+```bash
+python -m pip install -e .
+```
+
+The browser can be run with:
+
+```bash
+python -m simple_repository_browser
+```